The present invention relates to a verification information generation apparatus to verify an electronic mail, a method to generate verification information, and a verification information generation program. The invention more particularly verifies both legitimacy of an originating mail server and contents of electronic mail (e.g. sender, address, title, and message body information), and, for example, applies an electronic signature for a broadcast mail (e.g. a mail sent by mailing list) and verifies the electronic mail on the receiving side.